The application of the wireless communication has already become the mainstream technology of the consumer electronic products. In recent years, with the development of millimeter-wave frequency technology, the applications of high-speed data rate transmission of the wireless personal area network (WPAN) and general vehicular radar system both use the frequency up to tens of Giga Hertz. Because the wireless communication apparatus operating at millimeter-wave frequency can carry large number of data for transmission, it is quite suitable for applications of WPAN and the vehicular radar system. In millimeter-wave circuit technology, the design of system on chip (SoC) provides a small circuit size and facilitates mass production. In fact, the transmitter or receiver currently used in wireless communication apparatus has already been designed as a chip, and the antenna needs to be disposed at the front end of the transmitter or receiver to perform the signal transmission and reception.
In millimeter-wave communication applications, there are two methods to dispose the antenna. The first is to dispose the antenna on chip with the transmitter or receiver, which is called chip antenna. The second is to manufacture the antenna on the printed circuit board (PCB), and then integrate the antenna with the transmitter or receiver on chip by electrical connecting methods. Generally, the electrical connecting methods can be wire bonding, flip-chip, etc.
Please refer to FIG. 1(a), which shows an antenna 10 disposed on a chip in the prior art. The antenna 10 is the so-called Yagi chip antenna. As shown in FIG. 1(a), a resonant element 12 is disposed on the silicon substrate 11 of the chip. The resonant element 12 is connected to the feed-in point 13 for the antenna signal. Generally, the transmitter or receiver feeds the signal into the resonant element 12 via the feed-in point 13. The antenna signal can be resonated in the resonant element 12. Besides, the resonant element 12 also serves as the radiation element of the antenna 10 for transmitting the antenna signal. Please refer to FIG. 1(b), which shows the antenna 10 disposed on a printed circuit board 110. The advantage of the chip antenna is that the circuit of the resonant element 12 is integrated with the chip, which avoids the issues of the energy loss and impedance mismatching resulting from the substantial electrical connecting path such as the wire bonding or flip-chip. However, the material of the substrate 11 of the chip usually causes the energy loss, thereby deteriorating the radiation efficiency and radiation gain of the antenna. Please refer to FIGS. 1(c)-1(d), which show the radiation gain patterns of the antenna 10 of FIG. 1(a). FIG. 1(c) shows the radiation pattern of the signal of 60 GHz in the y-z plane, and FIG. 1(d) shows the radiation pattern of the signal of 60 GHz in the x-z plane. Generally, the radiation gain usually can reach 7˜9 dBi by using the Yagi antenna. However, by using this highly-directional Yagi antenna, the radiation gain and efficiency of the antenna in the chip still are only −10 dBi and about 10% respectively. This fully proves that the high-loss silicon substrate for manufacturing the chip greatly affects the efficiency of the antenna, which is a disadvantage of the chip antenna.
Compared to chip antenna, the method for manufacturing the antenna on the PCB has a lower cost and a lower energy loss of the signal, and the efficiency of the antenna usually can be above 80˜90%, which far surpasses the chip antenna with the efficiency of about 10%. However, for transmitting the signal from the chip to the antenna on the PCB, when applied in the millimeter-wave frequency band (e.g. 77 GHz), the conventional wire bonding or flip-chip technologies cause the issues of energy loss. Also the length of wire bonding causes radiation and the parasitic effects coming from capacitor and inductor due to the substantial circuit structure. When designing the antenna, these parasitic effects have to be considered in advance, and the compensation circuit shall be made with a more complex circuit design. Besides, the request for the process management of the wire bonding or flip-chip is relatively complicated, which increases lots of extra costs and the difficulty in manufacturing the antenna.
In order to overcome the drawbacks in the prior art, an integrated antenna and a method for operating an integrated antenna device are provided. The particular design in the present invention not only solves the problems described above, but also is easy to be implemented. Thus, the present invention has the utility for the industry.